There are three linetype settings to consider when setting up your drawings: LTSCALE, PSLTSCALE, & MSLTSCALE.
As you probably know if you’ve used AutoCAD for any length of time, LTSCALE controls the dash spacing in linetypes.
Model Space Linetype Scale
Set MSLTSCALE to 1 and it will scale linetypes in model space by the annotation scale. Turn this off by setting it to 0 (zero).
Paper Space Linetype Scale
This setting applies to linetypes shown through a viewport in a layout tab (paper space). Set PSLTSCALE to 0 (zero) and the linetype dash lengths will display per the LTSCALE in the drawing in which they reside. This means that if you show an XREF through a viewport and the PSLTSCALE is set to 0, the linetype scale will be controlled by the LTSCALE in the XREF, not the current drawing. However if you set PSLTSCALE to 1, the linetypes will be controlled by the LTSCALE in the current (paper space) drawing.
BONUS: Control Linetype Scale
The AutoCAD help file says, CELTSCALE “sets the current object linetype scaling factor. Sets the linetype scaling for new objects relative to the LTSCALE command setting. A line created with CELTSCALE = 2 in a drawing with LTSCALE set to 0.5 would appear the same as a line created with CELTSCALE = 1 in a drawing with LTSCALE = 1.”